Karsten Nohl, 28, told The Associated Press this week that he, working with others online and around the world, created a codebook containing how to get past the GSM standard encryption used to keep conversations on more than 3 billion mobile phones safe from prying ears.

Authorized users of the Enigma machine had access to a codebook which determined the base key value for a given period of time originally monthly or weekly, but over time this shifted to daily or even many times per day.

According to my codebook, to lay a foundation for similar transactions such as this, or for any past event, foundation equals the time, the location, any other witnesses, any other comments that were made, and the witness ` state of mind at the time of the incident.